import sys

def main():
    """ MAIN """
    num = int(input().strip())
    istr = sys.stdin.read()
    cmds = list(istr.splitlines())

    D = {}
    for i in cmds:
        if i[0] == "i":
            D[i[7:]] = 1
        elif i[0] == "f":
            if i[5:] in D:
                print("yes")
            else:
                print("no")

if __name__ == '__main__':
    main() import sys sys def main():
    """ MAIN """
    num = int(input().strip())
    istr = sys.stdin.read()
    cmds = list(istr.splitlines())

    D = {}
    for i in cmds:
        if i[0] == "i":
            D[i[7:]] = 1
        elif i[0] == "f":
            if i[5:] in D:
                print("yes")
            else:
                print("no") main """ MAIN """ num = int(input().strip()) num int(input().strip()) int input().strip() ().strip () input strip istr = sys.stdin.read() istr sys.stdin.read() sys.stdin.read sys.stdin sys stdin read cmds = list(istr.splitlines()) cmds list(istr.splitlines()) list istr.splitlines() istr.splitlines istr splitlines D = {} D {} for i in cmds:
        if i[0] == "i":
            D[i[7:]] = 1
        elif i[0] == "f":
            if i[5:] in D:
                print("yes")
            else:
                print("no") i cmds if i[0] == "i":
            D[i[7:]] = 1
        elif i[0] == "f":
            if i[5:] in D:
                print("yes")
            else:
                print("no") i[0] == "i" i[0] i 0 "i" D[i[7:]] = 1 D[i[7:]] D i[7:] i 7: 7 1 elif i[0] == "f":
            if i[5:] in D:
                print("yes")
            else:
                print("no") i[0] == "f" i[0] i 0 "f" if i[5:] in D:
                print("yes")
            else:
                print("no") i[5:] in D i[5:] i 5: 5 D print("yes") print "yes" print("no") print "no" if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    """ MAIN """
    num = int(input().strip())
    istr = sys.stdin.read()
    cmds = list(istr.splitlines())

    D = {}
    for i in cmds:
        if i[0] == "i":
            D[i[7:]] = 1
        elif i[0] == "f":
            if i[5:] in D:
                print("yes")
            else:
                print("no") def main():
    """ MAIN """
    num = int(input().strip())
    istr = sys.stdin.read()
    cmds = list(istr.splitlines())

    D = {}
    for i in cmds:
        if i[0] == "i":
            D[i[7:]] = 1
        elif i[0] == "f":
            if i[5:] in D:
                print("yes")
            else:
                print("no") main
import sys

def main():
    """ MAIN """
    num = int(input().strip())
    istr = sys.stdin.read()
    cmds = list(istr.splitlines())

    D = {}
    for i in cmds:
        if i[0] == "i":
            D[i[7:]] = 1
        elif i[0] == "f":
            if i[5:] in D:
                print("yes")
            else:
                print("no")

if __name__ == '__main__':
    main()